The present invention generally relates to the area of integrated communications network and more particularly to methods and mechanisms for controlling connections on one or more physical links supporting both fixed throughput (voice/video) and variable throughput (data) connections between an external network and a set of end nodes on an internal network.
Historically, businesses with external data links have included at least two separate and distinct sets of physical communications lines to their places of business. A first set of lines provide communication links between a public switched telephone network (PSTN) and a private branch exchange (PBX) system including phones and other telephony. A set of PSTN lines terminate at a business site at a PBX connected to a business"" internal phone lines. A second set of lines provide links between external data networks and internal local area networks (LANs) for the businesses. Examples of such lines are T1, E1, ISDN, PRI, and BRI. One may add a third line for supporting reception and/or transmission of video signals.
Certain inefficiencies may arise from maintaining two or more separate networks in a place of businessxe2x80x94one for voice calls and/or video calls, and the other for data calls. A first inefficiency is the increase in network hardware needed to accommodate the two physically separate line groups. A second inefficiency arises from the inability to share excess capacity that arises in a first line group with a second line group when a need arises for additional throughput on the second line group.
In recognition of the potential efficiencies arising from converging two physically and operationally distinct networks into a single network, the network technology industry has sought to define and implement a single, converged, network meeting the demands for all types of communications including voice, facsimile, data, etc. As a result, a new telephony/data transmission paradigm is emerging. The new paradigm is based upon a packet-based, switched, multi-media network. Data and voice, while treated differently at the endpoints by distinct applications, share a common transport mechanism.
When implemented, the new network communications standards and protocols will enable businesses to determine their total required communications throughput and base their leasing/purchasing decisions on the total need rather than purchasing/leasing distinct lines for specific operations. In addition to potentially reducing the amount of xe2x80x9cwirexe2x80x9d in the office or place of business, a business may increase the total pool of communications throughput at a lower cost than purchasing/leasing specific-purpose lines.
In recognition of the shortcomings of the prior software distribution facilities, a dynamic throughput allocation method is presented as well as a framework for carrying out the dynamic throughput allocation method. Throughput is a generic term referring to the total communications flow capabilities of a system, such as an interface between an external and internal network. For example, in a frequency divided communications interface, the throughput can be expressed in the total communications flow that is handled in a set of frequency divided channels serviced by the communications interface. Alternatively, in a time divided communications interface, the throughput can be expressed in the total communications flow that is handled by a set of time divided frames.
The method includes initially providing a network interface having a finite throughput. Data calls are allocated varying portions of the interface""s available throughput. In an embodiment of the present invention, an external link connected to the network interface supports voice and data calls, and may even carry video signals.
During the course of operation of the interface, a throughput allocation server assigns portions of the finite throughput supported by the interface to connections between ones of a set of internal nodes connected to an internal network and ones of a set of external nodes connected to ones of the set of internal nodes via the external link. While voice/video calls are typically assigned only a single channel or fixed portion of the throughput supported by the interface, data calls utilize portions of the throughput having a variable magnitude. In order to track the assigned portions of the total available throughput, the throughput allocation server includes a table describing the portions of the finite interface throughput assigned to each one of the connections. A throughput allocation controller monitors the available throughput.
When under heavy usage, such as simultaneously running a number of multimedia data calls, the throughput allocation controller determines that available (free) throughput is less than a minimum desired value, and in response de-allocates a portion, but not all, of the throughput previously allocated to at least one data call. The de-allocated portion is then returned to a pool of available (free) throughput of the communications interface.